Showing papers in "Immunology in 1989"

Production of interleukin-8 by human dermal fibroblasts and keratinocytes in response to interleukin-1 or tumour necrosis factor.

Abstract: Cultured normal human fibroblasts were stimulated to produce neutrophil-activating protein/interleukin-8 (IL-8) in response to IL-1 alpha (0.1-1000 U/ml) or tumour necrosis factor (TNF) alpha (0.1-1000 U/ml). Induction of mRNA for IL-8 in fibroblasts was rapid (within 30 min) and maximal responses were obtained with either 100 U/ml IL-1 alpha or 100 U/ml TNF alpha. Expression of mRNA for IL-8 was accompanied by the production of high levels of neutrophil chemotactic activity. IL-1 alpha (1000 U/ml), but not TNF alpha, induced mRNA for IL-8 in cultured normal human keratinocytes. The relevance of production of IL-8 by these cell types was evaluated further by comparing the local inflammatory effects of IL-1 alpha, TNF alpha and IL-8. Intradermal injection of either recombinant IL-8, IL-1 alpha or TNF alpha lead to a similar in vivo effect, i.e. dose-dependent accumulation of lymphocytes and polymorphonuclear leucocytes at sites of injection. The in vivo attraction of neutrophils and lymphocytes to the site of injection by TNF or IL-1 (which is not chemotactic for neutrophils or lymphocytes in vitro), may be partly mediated by locally produced IL-8. Thus, IL-8 may be a vital participant in the cascade of interacting cytokines that is induced by tissue injury and immunologically induced inflammation.

A diffusible lymphokine produced by CD8+ T lymphocytes suppresses HIV replication.

Abstract: Peripheral blood CD8+ T lymphocytes from human immunodeficiency virus (HIV)-infected individuals suppress replication of HIV in peripheral blood mononuclear cells (PBMC). This anti-viral activity appears to be mediated in part by a diffusible factor. Production of this lymphokine varies among infected individuals and may reflect the intrinsic ability of an individual's CD8+ cells to control HIV infection. In some cases in which factor activity is not apparent, contact of the CD8+ cells with infected CD4+ cells can produce for suppression of virus replication. These observations could lead to approaches for enhancing anti-viral responses in HIV-infected individuals.

Antibodies to IFN-gamma prevent immunologically mediated intestinal damage in murine graft-versus-host reaction.

Abstract: We have tested the hypothesis that interferon-gamma (IFN-gamma) plays a role in the enteropathy of graft-versus-host reaction (GVHR) by treating host mice with a monoclonal antibody directed at this mediator. Two models of GVHR were examined. In the mild proliferative GVHR, which occurs in adult unirradiated (CBA x BALB/c)F1 mice given parental spleen cells, anti-IFN-gamma slightly inhibited the development of splenomegaly and the activation of natural killer (NK) cells in GVHR. Anti-IFN-gamma had no effect on splenomegaly or generation of anti-host cytotoxic T lymphocytes (CTL) during the more severe GVHR in adult BDF hosts, but inhibited the weight loss and mortality normally found in this GVHR. Despite these variable effects on systemic GVHR, anti-IFN-gamma treatment abolished the crypt hyperplasia and increased counts of intraepithelial lymphocytes (IEL) normally found in the jejunum of (CBA X BALB/c)F1 mice with GVHR. In parallel, anti-IFN-gamma-treated BDF1 mice with GVHR did not develop the villus atrophy and intense crypt hyperplasia found in untreated GVHR hosts. These results support the view that IFN-gamma is essential for the development of enteropathy in GVHR and we propose that this mediator may also be involved in the pathogenesis of clinical enteropathies in man.

Control by IFN-gamma and PGE2 of TNF alpha and IL-1 production by human monocytes.

Abstract: There have been suggestions that the production of pro-inflammatory mediators by human monocytes in response to interferon-gamma (IFN-gamma) may be controlled by changes in prostaglandins. Therefore we investigated tumour necrosis factor alpha (TNF alpha) and interleukin-1 (IL-1) activities and prostaglandin E2 (PGE2) levels in the supernatants of highly purified human monocytes cultured for 18 hr with recombinant human IFN-gamma. IFN-gamma (100 U/ml) did not stimulate monocytes isolated by counter-current centrifugal elutriation for detectable TNF alpha or IL-1 activities, or PGE2 production. However, IFN-gamma synergistically enhanced lipopolysaccharide (LPS)-induced TNF alpha and IL-1 activities. In contrast, there was no consistent change in PGE2 levels upon addition of IFN-gamma to LPS-treated monocyte cultures. The TNF alpha and IL-1 activities induced by LPS and by LPS with IFN-gamma were reduced by PGE2, and stimulated by indomethacin. As reported previously for IL-1 activities, the regulation by cyclo-oxygenase products of TNF alpha activities reflected predominantly a control of the production of immunoreactive TNF alpha, rather than the measurement of TNF alpha bio-activity. However, the addition of indomethacin or PGE2 to monocyte cultures did not change the extent of IFN-gamma synergy with LPS for increased TNF alpha and IL-1 activities. The results of this study suggest that, despite control by cyclo-oxygenase products of TNF alpha and IL-1 production in human monocytes, IFN-gamma may enhance TNF alpha and IL-1 activities independently of this regulatory mechanism. These findings are contrary to those suggested for the regulation by prostanoids of IL-1 production by murine macrophages.

Soluble malarial antigens are toxic and induce the production of tumour necrosis factor in vivo.

Abstract: Heat-stable soluble products of rodent malarial parasites induce activated peritoneal macrophages to secrete tumour necrosis factor (TNF) in vitro. Since heat-stable parasite antigens are known to be present in the circulation of patients with malaria and it has been suggested that much of the pathology of malaria is due to TNF, we investigated the ability of such antigens to induce the production of TNF in vivo and to be toxic to mice. Injection of antigens obtained from Plasmodium yoelii or from P. berghei into mice which had previously received the macrophage-activating agent Propionibacterium acnes induced the release of TNF into the serum in amounts equivalent to the maximum release induced by bacterial lipopolysaccharide (LPS). Specific antiserum blocked the ability to the boiled soluble antigens, but not of LPS, to induce release of TNF. Similarly, vaccination specifically inhibited the release of TNF into the serum in response to subsequent stimulation with the antigens, but not with LPS. Mice made hypersensitive to the lethal action of TNF by pretreatment with D-galactosamine were killed in a dose-related fashion by administration of antigen preparations; addition of specific antiserum or prior vaccination with the antigens protected such mice, but not those given LPS, from death. We conclude that, in malaria, soluble antigens derived from the parasites may act like a toxin by stimulating the production of TNF, an important mediator of endotoxic shock, and that immunization with such antigens may diminish TNF secretion and consequently many of the clinical manifestations of the disease.

Suppression of immune responses by dendritic cells infected with HIV.

Abstract: Evidence of human immunodeficiency virus (HIV) replication both in the skin Langerhans' cells of AIDS patients (Tschachler et al., 1987) and in normal, peripheral blood dendritic cells (DC) (Patterson & Knight, 1987; Knight & Patterson, 1989) suggests that infection of these antigen-presenting cells may contribute to the immunosuppression seen in AIDS. Support for this hypothesis is now provided by experiments in which the capacity of DC infected in vitro to present mitogen to normal syngeneic lymphocytes was measured. Infecting DC with HIV before culturing with lymphocytes inhibited mitogen-stimulated cell proliferation. Viral DNA was detected in DC in these cultures by in situ hybridization but, in addition, HIV was also present in a small proportion of lymphocytes. However, introducing an inhibitor of virus replication, 2',3' dideoxyadenosine, after infection of the DC but before culturing with lymphocytes, blocked growth of HIV in lymphocytes. In these latter experiments mitogen proliferation responses were still suppressed. Infection of DC could, therefore, cause immunosuppression in AIDS, both by direct effect on antigen-presentation and by the transfer of HIV to T cells.

Lymphocyte subsets in jejunal and ileal Peyer's patches of normal and gnotobiotic minipigs.

Abstract: The size and location of Peyer's patches (PP) in the jejunum and ileum and their composition of lymphocyte subsets (B, CD2+, CD4+, CD8+) have been studied in conventional and gnotobiotic Gottingen minipigs. Each PP in the small intestine remained at the same site and was of comparable length between 2 and 12 months of age. In 1.5-month-old conventional minipigs the histology of the compartments differed between the continuous PP in the terminal ileum (ilPP) and the discrete PP in the jejunum (jejPP). No such difference was seen in gnotobiotic or in 12-month-old animals. The composition of lymphocyte subsets showed striking differences with significantly more B and less T, CD4+ and CD8+ cells in ilPP in 1.5-month-old minipigs in comparison with 12-month-olds. Mesenteric lymph nodes and jejPP displayed a typical pattern of lymphocyte subsets. The size of the lymphocyte compartments in PP and their cellular composition depends largely on age and microbial influences from the gut lumen, which might be of major importance for studies on the function of the gut-associated immune system in the pig.

Theileria annulata and T. parva infect and transform different bovine mononuclear cells.

Abstract: Bovine peripheral blood mononuclear cells (PBMC) were labelled with monoclonal antibodies recognizing bovine MHC class II, sIgM, monocyte, T-helper and T-cytotoxic cell phenotypes. They were sorted into positive and negative populations with a fluorescence-activated cell sorter (FACS). The cell populations were infected in vitro with sporozoites of either Theileria annulata or T. parva, and the degree of infection and transformation determined. The results showed that despite the many similarities between these two parasites, they infected different cells of the immune system. T. annulata preferentially infected MHC class II-positive cells but did not infect T cells. Monocytes were infected very efficiently by T. annulata but were uninfectable with T. parva. B cells were infected much more efficiently by T. annulata than T. parva. Cell lines derived from infections with T. annulata were analysed phenotypically. Virtually all reactivity was lost for the anti-sIgM and the anti-monocyte monoclonal antibodies post-infection and no T-cell markers were detected.

Antibody-forming cell induction during an early phase of germinal centre development and its delay with ageing.

Abstract: The present study was initiated to determine if an early phase of germinal centre (GC) development is associated with the generation of antibody-forming cells (AFC). Germinal centres in draining lymph nodes from immune mice were examined histochemically after secondary immunization for the presence of AFC at both the light and electron microscopic levels. Additionally, peanut agglutinin (PNA) high (Hi) GC B cells were isolated, placed in cell culture and specific antibody production was monitored at successive intervals. Electron microscopy showed that plasma cells in all stages of differentiation were present within GC at 3-5 days and to a lesser extent at 7 days following antigenic challenge. Furthermore, PNAHi GC B cells obtained between Days 3 and 5 spontaneously produced specific IgG when placed in culture. Germinal centre B cells isolated either before or after this period did not produce antibody without the addition of T-cell cytokines. Induction of AFC in GC occurred at the time when GC B cells acquire follicular dendritic cell (FDC)-derived, immune complex-coated bodies (iccosomes) and process and present this antigen to helper T cells. This suggested a causal relationship between iccosome release and AFC induction. Support for this was obtained by examination of AFC induction in aged mice where iccosome release has not been observed. Peanut agglutinin-positive GC B cells isolated from aged mice on Days 3-5 after antigen challenge failed to spontaneously produce specific antibody. Collectively, these data show that GC development 3-5 days after booster immunization results in AFC generation and suggests a role for FDC iccosomes in their induction.

Zinc requirement for macrophage function: effect of zinc deficiency on uptake and killing of a protozoan parasite.

Abstract: The effects of suboptimal levels of zinc, an essential trace element, on the ability of murine macrophages to associate with and destroy a pathogenic parasite, Trypanosoma cruzi, were evaluated. Young adult A/J mice were fed zinc-deficient, zinc-adequate or restricted amounts of a zinc-adequate diet for 28 days. On the basis of weight loss and parakeratosis, the zinc-deficient mice were further divided into moderately and severely zinc-deficient on Day 28. Both the percentage of mouse peritoneal macrophages (MPM) with associated parasites and the number of parasites per 100 macrophages were significantly lower for macrophages from moderately and severely deficient mice compared to MPM from mice fed restricted or zinc-adequate diet. Furthermore, MPM from both zinc-deficient groups of mice killed fewer internalized parasites than did MPM from restricted or zinc-adequate mice. Pretreatment of MPM from zinc-deficient mice with 5 micrograms zinc/ml for 30 min completely restored both their capacity to take up and kill the parasites. Other trace metals tested, including copper, manganese and nickel, failed to reverse the effects of zinc deficiency. These results point to an important role for zinc in the biochemical events associated with macrophage uptake and killing of the parasite.

Rapid recovery of lung histology correlates with clearance of influenza virus by specific CD8+ cytotoxic T cells

Abstract: Previous studies have shown that influenza nucleoprotein (NP)-specific cytotoxic T-cell clones do not prevent influenza infection of mice but lead to a more rapid viral clearance and recovery of the host Here we examine the histology of the lung to see if viral clearance by cytotoxic T cells (Tc) correlates with recovery of pulmonary pathology or if it is in any way deleterious Intransasal (in) A/X31 virus infection of BALB/c mice produces lung tissue changes lasting 8-10 days in BALB/c mice, with the most severe abnormalities appearing between Days 4 and 6 (eg loss of epithelium, airway obliteration, peribronchiolar and perivascular cell accumulation) The transfer of Tc clone T9/13 into in-infected BALB/c mice induces a transient enhanced loss of epithelium on Day 4, while by Day 6 epithelial abnormalities are much reduced in the lung compared to control infected mice This correlates with a significant reduction in lung virus titres by Day 6; by Day 8 virus is cleared in Tc recipients and lung histology is normal Another Tc clone (T5/5) with greater cytolytic activity resulted in significant recovery of the lung tissues by Day 4 Tc clones also resulted in enhanced perivascular infiltration of cells and variation in the infiltrating cell type Quantification in our system required careful attention to the level of the airway assessed These histological findings showing an enhanced tissue recovery support the previous assessment of reduced lung viral levels following the transfer of Tc cells, and show that a transient increase in lung pathology can occur

Characteristics of human synovial fibroblast activation by IL-1 beta and TNF alpha

Abstract: Human synovial fibroblast cell lines (HSN), established from tissues obtained from the knee joints of arthritis patients undergoing arthoplasty, were used to investigate the effects of human interleukin-1 (IL-1) beta and tumour necrosis factor (TNF)alpha on proliferation and prostaglandin E2 (PGE2) secretion IL-1 beta and TNF alpha were equipotent stimulators of HSN proliferation Classical non-steroidal anti-inflammatory drugs and glucocorticoids significantly augmented this effect In addition, IL-1 beta and TNF alpha were potent inducers of PGE2 production while exogenous PGE2 was growth inhibiting These data suggest that the secretion of PGE2 by monokine-stimulated HSN exerts a negative feedback signal Further examination of IL-1 beta- and TNF alpha-induced PGE2 secretion revealed IL-1 beta to be a more potent stimulator; however, this observation may be due, in part, to differences in the kinetics of induction Rabbit anti-IL-1 beta and anti-TNF alpha specifically neutralized both proliferation and PGE2 production induced by these monokines, but anti-IL-1 beta (or anti-IL-1 alpha) did not block TNF alpha activity It is unclear whether TNF alpha stimulates HSN to produce IL-1, but the antibody data suggest that extracellular IL-1 is not responsible for TNF alpha in vitro activity

Oestradiol- and testosterone-mediated effects on the immune system in normal and autoimmune mice are genetically linked and inherited as dominant traits.

Abstract: The influence of sex steroids on cutaneous delayed-type hypersensitivity (DTH) and antibody responses to oxazolone (OXA) in autoimmune and normal mouse strains has been investigated. The results show that: (i) treatment with 17 beta-oestradiol (E2) suppresses DTH responses and stimulates antibody responses in MRL, B6 and C3H mice, suppresses DTH in DBA/1 mice, while having no effects on DTH or antibody responses in BALB/c and NFR/N mice. (ii) Treatment with testosterone suppresses the antibody response in all studied strains (MRL, B6, BALB/c and DBA/1) while down-regulating the DTH response only in MRL and B6 but not in BALB/c or DBA/1. (iii) Neither the lympho-proliferative (lpr) gene, which accelerates autoimmune disease, nor the H-2 genes seem to be directly related to the effects of sex hormones on the immune system. (iv) Susceptibility to oestrogen- and testosterone-mediated suppression of DTH but not oestrogen-mediated enhancement of antibody response are inherited as dominant traits. The results are discussed in the context of certain autoimmune diseases known to be influenced by sex hormone manipulations.

Dendritic cells and IFN-alpha-producing cells are two functionally distinct non-B, non-monocytic HLA-DR+ cell subsets in human peripheral blood.

Abstract: At least two distinct HLA-DR+ cell subsets lacking surface markers specific for B cells, monocytes or other known lineages are present in human peripheral blood. One subset is non-adherent to plastic, produces interferon-alpha (IFN-alpha) when incubated with cytomegalovirus-infected target cells and provides an accessory function required for natural killer (NK) cell-mediated lysis of such cells. These non-adherent HLA-DR+ cells express the surface antigen recognized by antibody anti-D44 and do not stimulate mixed leucocyte reaction (MLR). The other HLA-DR+ cell subset is loosely adherent to plastic, produces only minimal levels of IFN-alpha when incubated with cytomegalovirus-infected target cells and does not provide the accessory function required for NK cell-mediated lysis of such cells. These HLA-DR+ cells stimulate a strong MLR, do not express D44 antigen and meet the criteria of dendritic cells (DC) morphologically and functionally.

Human granulocyte chemotactic peptide (IL-8) as a specific neutrophil degranulator - comparison with other monokines

Abstract: The influence of human monocyte-derived chemotactic peptide (GCP/IL-8) on degranulation of neutrophils was investigated in relation to that of other monokines. GCP/IL-8 promoted a dose-dependent release of lactoferrin from specific granules but had no effect on enzyme release from primary granules. From the other monokines that were tested, tumour necrosis factor alpha (TNF alpha) also induced degranulation, while IL-1 beta and IL-6 scored negatively. TNF alpha-induced lactoferrin release was enhanced by cytochalasin B pretreatment of the granulocytes, while GCP/IL-8-promoted degranulation was not. In contrast to GCP, TNF alpha also caused the release of LDH, suggesting a non-specific cell destruction. These observations further support the view that, unlike the other monokines, GCP/IL-8 is a true and specific granulocyte activator.

Immunoregulatory properties of bone marrow-derived cells in the iris and ciliary body

Abstract: Iris and ciliary body of mouse eyes have been examined for the presence of bone marrow-derived cells possessing the capability of functioning as antigen-presenting cells (APC). We have determined that iris and ciliary body contain significant numbers of cells bearing T200, indicating their bone marrow origin. Most of these express the F4/80 marker typically found on mature macrophages. However, approximately one-third of the cells express Ia and a similar number express Mac-1 markers. Virtually none of the cells express Thy-1 or surface immunoglobulin. Whole preparations of excised iris/ciliary body, or single cell suspensions prepared from these tissues were then assayed for their capacity to induce proliferation among allogeneic lymphocytes. It was discovered that iris/ciliary body tissues or cells did not function as alloantigen-presenting cells, although tissue and cells derived from the corneal limbus were allostimulatory. In addition, iris/ciliary body tissues and cells displayed the ability to suppress mixed lymphocyte reactions to which they had been added as regulatory cells. We conclude that normal iris and ciliary body contain bone marrow-derived cells that fail to function as alloantigen-presenting cells. However, cells were present that have the capacity to inhibit alloimmune lymphocyte proliferation. The strategic location of inhibitory cells in the tissues that line the anterior chamber of the eye raises the possibility that these cells may play a role in the phenomenon of immunological privilege that is characteristic of this site.

Chemical composition and tissue distribution of the human CDw44 glycoprotein.

Abstract: The CDw44 glycoprotein was purified from 2.3 x 10(11) CD3+ CD4+ CD8- T-chronic lymphocytic leukaemia (CLL) cells using F10-44-2 monoclonal antibody affinity chromatography, DEAE-Sepharose anion-exchange chromatography, passage down carboxymethyl (CM)-Sepharose cation-exchange columns, wheat germ lectin affinity chromatography and gel-permeation chromatography. On elution in non-ionic detergents from the DEAE column, two distinct peaks of antigen activity were obtained. The CDw44 glycoprotein in each peak was a glycoprotein of 85,000 MW, but the amino acid composition of the peaks was noticeably different. Carbohydrate compositions showed that each peak contained approximately 30% (w/w) carbohydrate, the composition suggesting both O-linked and complex N-linked glycans. Modulation studies with the F10-44-2 antibody on normal peripheral blood mononuclear cells (PBMC) demonstrated that the CDw44 glycoprotein of T cells consisted of one fraction that was readily modulated, and the other which was resistant to modulation. Detailed tissue distribution studies for CDw44 were performed using the F10-44-2 antibody on frozen sections of human tissues. CDw44 has a restricted tissue distribution, but is found on many highly diverse cell types (e.g. T lymphocytes, smooth muscle cells, some secretory glands, skin epithelial cells).

Presence of tumour necrosis factor or a related factor in human basophil/mast cells.

Abstract: The observation that mast cell products and cachectin/tumour necrosis factor (TNF) mediate similar responses suggested an investigation of cultured human basophil/mast cells for production of TNF. Using in situ hybridization and the avidin biotin-complex (ABC) immunoperoxidase method, we have demonstrated the presence of TNF mRNA in the cytoplasm and TNF protein in the granules of individual human basophil/mast cells. The production of TNF by these cells could explain many of their reported functions.

The tissue distribution of T lymphocytes expressing different CD45 polypeptides.

Abstract: The distribution of T lymphocytes expressing the different polypeptides of the leucocyte common antigen (LCA) family detected by CD45R and UCHL1 antibodies has been studied in normal lymphoid tissues. In the thymus most cortical thymocytes express UCHL1 and co-express CD4 and CD8. The more mature membrane CD3+ (mainly medullary) T cells are heterogenous and may express both UCHL1 and CD45R weakly or be restricted to display CD45R or UCHL1 alone. In the medulla both the CD45R+ and UCHL1+ subpopulations contain single positive CD4 and CD8 cells. In tonsils, germinal centre T cells are almost exclusively UCHL1+, CD4+ and a proportion also express HNK-1 (Leu 7) antigen. In the paracortical areas approximately equal numbers of CD45R+ and UCHL1+ cells are found but these separately occupy nests of cells containing one or the other type. Again, both CD45R+ and UCHL1+ cells include single CD4+ and CD8+ lymphocytes. A small proportion (less than 5%) of strongly CD45R+, UCHL1+ double-stained cells are also seen, and these probably represent recently activated lymphocytes. In the gut, small clusters of such strongly double-labelled cells are in the submuscular mucosae while cells of the lamina propria are almost exclusively UCHL1+. Many intra-epithelial lymphocytes are only weakly positive or negative for UCHL1 and appear to be CD45R-. These results are consistent with the view that expression of different CD45 polypeptides identifies successive stages of thymocyte-T-cell maturation and that following their thymic education, unprimed T lymphocytes are CD45R+, while primed memory T cells are UCHL1+. These populations occupy different microenvironments.

A role for CD4+ but not CD8+ T cells in immunity to Schistosoma mansoni induced by 20 krad-irradiated and Ro 11-3128-terminated infections.

Abstract: The role of CD4+ (L3/T4+) and CD8+ (Lyt-2+) T cells in immunity to Schistosoma mansoni induced by 20 krad-irradiated and Ro 11-terminated infections in mice was investigated directly by in vivo depletion of these subsets with cytotoxic rat monoclonal antibodies (mAb). Effective physical depletion was demonstrated by flow cytometric analysis and immunohistochemical staining. Functional depletion of helper activity following anti-CD4 treatment was indicated by an abrogation of concanavalin A(Con A)-induced colony-stimulating factor (CSF) release, while anti-CD8 treatment had no effect in these assays. Pre-existing S. mansoni-specific antibody levels were unaffected by anti-CD4 and anti-CD8 treatment. In vivo depletion of CD4+ T cells resulted in a dramatic reduction in immunity induced by one (up to 100%) and two (up to 70%) vaccinations with 20 krad-irradiated cercariae and also of resistance induced by Ro 11-attenuated infections (up to 100%). Depletion of CD8+ T cells had no effect on resistance induced by any of the vaccination protocols investigated. A correlation was observed between resistance and T cell-induced, macrophage-mediated killing of schistosomula in vitro, both of which were abrogated following anti-CD4 treatment but were unaffected by CD8+ T-cell depletion. The possible role of CD4+ T cells in vivo and the implications for vaccine development are discussed.

Natural killer cell function is not diminished in the healthy aged and is proportional to the number of NK cells in the peripheral blood.

Abstract: We studied natural killer (NK) cell subsets and NK function in young (25-35 years) and aged (75-84 years) persons by means of the single-cell assay. The subjects admitted to the study all fulfilled the SENIEUR health criteria in order to avoid confounding factors such as underlying disease or the influence of medication. We found no significant difference in the NK function between healthy young and aged persons on a per cell basis. A new application of the two-wavelength immunofluorescence technique during the single cell assay made it possible to define the phenotypes of the conjugate-forming cells responsible for the natural killer function. Most of the conjugate-forming cells were CD 16-positive, and half of these were also positive for Leu 7. The CD 16 antigen disappeared from the cell surface during the effector:target interaction. T-cell markers were found on some of the conjugate-forming cells but not on the strongly bound effector cells. The NK cell function was directly proportional to the number of NK (CD 16) cells in the peripheral blood.

Serum cytokine changes in systemic vasculitis.

Abstract: Cytokines are known to alter a number of vascular tissue cell functions The aim of this retrospective study was to determine serum cytokine levels in patients with vasculitis and to analyse the possible relation to the severity of the disease Tumour necrosis factor alpha (TNF alpha), interleukin-1 (IL-1)beta, IL-2, interferon (IFN)- and IFN-gamma were assayed in 33 patients with polyarteritis nodosa (PAN) or Churg and Strauss angiitis (CSA), and three with Wegener granulomatosis (WG) Serum cytokine changes were observed in most patients with active disease, ie before treatment was started In the majority of patients with PAN or CSA, there was a marked increase in serum IFN-alpha and IL-2 levels, while TNF-alpha and IL-beta levels were moderately elevated Serum IFN-gamma remained undetectable in all but one of these patients In patients with WG, serum IFN-alpha and IL-2 levels were also elevated, whereas IL-1 beta, IFN-gamma and TNF alpha levels remained within normal limits In paired samples of patients with PAN, IFN-alpha and IL-2 levels were significantly higher before than after treatment These preliminary data suggest that a particular pattern of cytokine changes is associated with vasculitis and that cytokines might be involved in the pathogenesis of PAN/CSA and WG Prospective studies are warranted to determine whether cytokines could be considered for the monitoring of disease activity and therapy

Site-directed differences in the immune response to the fetus

Abstract: Major differences in the maternal immune response to the fetus were observed in the placentomes and in the interplacentomal regions of the pregnant sheep uterus. Firstly, fewer lymphocytes were detected in the placentomes compared to the interplacentomal regions and to non-pregnant uterine tissue (Lee, Gogolin-Ewens & Brandon, 1988). Secondly, a large population of CD45R+ granulated lymphocytes was uniformly distributed in the interplacentomal uterine epithelium throughout pregnancy but never in the syncytial layer of the placentomes. Thirdly, monoclonal antibodies specific for the CD5 antigen consistently stained the endothelium of blood vessels within the placentomes but never blood vessels in the interplacentomal areas. Finally, OLA class I antigens were present on the interplacentomal uterine epithelial cells and on the maternal stromal cells, but no staining of the trophoblast or syncytium was observed. These observations suggest that different mechanisms to prevent immune rejection of the fetus may operate in the placentomes where trophoblast invasion of the maternal tissue occurs compared to the interplacentomal regions.

The role of macrophages in the immunoadjuvant action of liposomes: effects of elimination of splenic macrophages on the immune response against intravenously injected liposome-associated albumin antigen.

Abstract: The primary antibody response to intravenously administered and liposome-associated human serum albumin (HSA) was studied in mice under conditions where no response could be detected against the non-liposome-associated form of the antigen. The positive response against the antigen, entrapped in and/or exposed on the surfaces of liposomes, thus resulted from the adjuvant action of the liposomes. In mice intravenously injected with dichloromethylene diphosphonate (C12MDP) also entrapped in liposomes, all red pulp macrophages, marginal metallophilic macrophages and marginal zone macrophages had disappeared from the spleen 2 days after administration. Twenty-two days after such a treatment red pulp macrophages and marginal metallophilic macrophages had reappeared, but marginal zone macrophages were still absent. In mice injected with liposome-associated HSA at 2 days after treatment with the C12MDP liposomes, anti-HSA responses were severely depressed, but administration of the liposome-associated antigen 22 days after C12MDP liposomes elicited a normal response. These results point to a role of splenic macrophages in the processing of liposome-associated antigens, but marginal zone macrophages, which are located close to the open ends of the white pulp capillaries and thus are the first macrophages to meet the antigens arriving in the marginal zone are not required.

Surface expression of differentiation antigens on lymphocytes in the ileal and jejunal Peyer's patches of lambs.

Abstract: The surface phenotype of lymphocytes in the ileal (IPP) and jejunal (JPP) Peyer's patches (PP) of lambs was compared using flow cytometry and immunohistology with a panel of monoclonal antibodies (mAb). The B-cell markers p220, BAS9A and surface Ig molecules were detected on 70-95% of cells from the IPP. T-cell markers were detected on less than 1% of IPP lymphocytes, confirming that the IPP in lambs contains virtually only B lymphocytes. The JPP contained a lower proportion of B cells and 16% T cells, nearly all of which expressed the CD4 molecule. Interestingly, the reactivity of a fourth B-cell markers, BAQ44a, differed from this pattern; only 12% of IPP lymphocytes were positive whereas 70% of JPP lymphocytes expressed this marker. A majority of both IPP and JPP lymphocytes (80-95%) expressed the cell adhesion molecules CD11a (LFA-1) and LFA-3. Other adhesion molecules, such as CD2 and CD44, were expressed by fewer cells from the IPP than from the JPP. MHC class I antigens were detected on more than 95% of lymphocytes from both the IPP and JPP. In the case of MHC class II antigens, more positive cells occurred in the IPP (greater than 95%) than in the JPP (80%). The in situ localization of cell-surface antigens was assessed by immunohistology. CD4+ T cells occurred in the interfollicular T-cell regions and in JPP follicles, whereas CD8+ T cells localized only in the interfollicular regions and were absent from follicles. The pattern of expression of B-cell markers, adhesion molecules and MHC antigens indicated that a gradient of increasing maturity of B cells existed within follicles from the base towards the dome region. The data presented here lend support to the notion that the IPP in lambs represents a novel B-cell lymphoid tissue with a function different from that of the conventional Peyer's patches found in the jejunum.

Immobilized anti-CD3 monoclonal antibodies induce accessory cell-independent lymphokine production, proliferation and helper activity in human T lymphocytes.

Abstract: Monoclonal antibodies (mAb) directed against the human CD3 molecular complex are able, when immobilized on the plastic of microtitre wells, to induce accessory cell-independent T-cell proliferation. In this study, we show that the anti-CD3 mAb CLB-T3/3 induces strong T-cell stimulation that is proportional to the density of the immobilized antibody. T cells, optimally stimulated with plastic-immobilized CLB-T3/3, showed a five-fold higher proliferation compared to cells that were stimulated with soluble anti-CD3 in the presence of accessory cells. The difference in magnitude of proliferation was found to be correlated with the expression of the CD25 (TAC) antigen and the production of interleukin (IL)-2, but not with the number of high-avidity IL-2 receptors expressed on the surface of these differentially activated cells. In addition, immobilized CLB-T3/3 initiated the production of interferon-gamma (IFN-gamma), but not of IL-4, in purified T lymphocytes. Coated anti-CD3 mAb induced helper activity in T cells for IgM and IgG production by B lymphocytes. Whereas addition of IL-1 or IL-2 had only a moderate effect on T-cell proliferation induced by immobilized anti-CD3 mAb, helper activity was strongly enhanced in the presence of these factors. This T-cell activation system may prove useful for a standardized analysis of both activation requirements and immunoregulatory capacities of human T cells.

Immunochemistry at interfaces.

Abstract: The immunochemistry of antibody binding to solid-phase immobilized antigen is reviewed. Experimental data are compared with different theoretical models of reaction mechanisms at solid-liquid interfaces. It was found that reactions at the solid-liquid interface can become limited by the diffusion rate due to depletion of reactants close to the surface, even though the intrinsic bimolecular reaction at the surface is reaction-rate limited. The forward reaction-rate constant decreases with increasing concentration of bound antibodies at the surface, and when not limited by diffusion the forward reaction rate can be more than 1000-fold slower than the corresponding reaction in a liquid solution. Possible explanations for this phenomenon are discussed. The dissociation of bound antibodies is a slow process at solid phases. The antigen-antibody complexes formed are practically irreversible. Some evidence is presented which indicates that the stability of these complexes can be due to attractive lateral interactions between bound antibodies.

Activation of human neutrophils by substance P: effect on FMLP-stimulated oxidative and arachidonic acid metabolism and on antibody-dependent cell-mediated cytotoxicity.

Abstract: We show that the neuropeptide, substance P (SP), a putative mediator of neurogenic inflammation, is a potent regulator of mature, human neutrophil function. SP increased neutrophil cytotoxic activity against an antibody-coated target (P815 cells) in a dose-dependent manner. The maximal effect was noted at an SP concentration of 10(-4) M, when cytotoxicity increased from 4.7 +/- 0.9% to 33.4 +/- 10.3%. This effect was not due to toxicity of SP against the target cells and was antibody-dependent. The level of cytotoxic activity induced by SP was comparable to that described for a number of cytokines, such as GM-CSF, under identical assay conditions. SP-induced cytotoxicity was 73.1 +/- 5.8% of that produced by an optimum concentration of conditioned medium known to contain a number of cytokines which activate mature neutrophils. In addition, SP enhanced FMLP-stimulated superoxide anion production by neutrophils in a dose-dependent fashion. Neutrophils preincubated with medium or 7.5 x 10(-5) M SP and then stimulated with 10(-7) M FMLP produced 7.9 +/- 2.7 and 29.9 +/- 3.7 nmol superoxide anion/10(6) cells, respectively. This priming effect of SP was rapid in onset (less than 15 min) and was maximal from 15 to 60 min, after which it declined. It was not reversed by washing the cells and was temperature dependent. SP did not shift the dose-response curve to FMLP to the left, but it enhanced the response to FMLP in the concentration range 10(-8)-10(-6) M. Similarly SP enhanced LTB4 and 5-HETE production by FMLP-stimulated but not calcium ionophore-stimulated neutrophils. Therefore, these data provide evidence that SP regulates a number of neutrophil functions and suggests a mechanism whereby the nervous system may affect the immune response. Furthermore, the regulatory effects of SP on the neutrophil functions studied appear to be similar to those of a number of cytokines that have been previously implicated in inflammation.